Method and apparatus for an active convertor dolly

ABSTRACT

The disclosure is directed at a method and apparatus for an active convertor dolly for use in a tractor-trailer configuration. In one embodiment, the apparatus includes a system to connect a tractor to a trailer. The apparatus further includes a charge generating system for translating the mechanical motions or actions of the dolly into electricity or electrical energy so that this energy can be used to charge a battery or to power other functionality for either the dolly or the tractor-trailer. The active dolly may also operate to assist in shunting the tractor-trailer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/560,528, filed Sep. 4, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/608,098 filed May 30, 2017 under the titleMETHOD AND APPARATUS FOR AN ACTIVE CONVERTER DOLLY, the content of whichis hereby expressly incorporated by reference into the presentapplication.

FIELD

This disclosure relates generally to the road transportation industry.More specifically, the disclosure is directed at a method and apparatusfor an active convertor dolly.

BACKGROUND

Transportation of goods across road networks is typically accomplishedby way of a transport truck to which a transport trailer is attached.The truck provides the engine and the trailer provides the cargo spaceto transport goods within. A recent trend in the transportation of goodsby road is the expansion of the size of transport trucks. This expansionis accomplished by both larger trucks and larger trailers. Fewer tripswith larger loads can be more efficient in certain circumstances. Oneway to achieve larger loads is to add a pup trailer behind the maintrailer. A transport trailer with the pup trailer may be called atransport trailer train.

The typical equipment used to attach a pup trailer to a transporttrailer is called a converter dolly. Current convertor dollies arepassive and limited in their use and application.

Therefore, there is provided a novel method and apparatus for an activeconvertor dolly.

SUMMARY OF THE DISCLOSURE

The disclosure is directed at a novel method and apparatus for an activeconverter dolly that provides enhanced applications. In anotherembodiment, the disclosure may be directed at an active dolly converterthat assists in the fuel economy of transport trucks.

In one aspect of the disclosure, there is provided an active converterdolly including a frame portion including a trailer/truck connectingportion and a trailer connecting portion; a charge generation systemmounted to the frame portion; and a control system for controlling theactive converter dolly.

In another aspect the trailer/truck connecting portion includes a fifthwheel assembly. In a further aspect, the trailer/truck connectingportion includes a hitch. In yet another aspect, the charge generationsystem includes a system for generating electricity from mechanicalactions of the active converter dolly; and a battery for storing theelectricity. The charge generation system further includes a set ofmotors for controlling the wheels of the dolly.

In yet another aspect, the control system includes a control module formonitoring a battery level; and a dolly control system for controllingthe charge generation system. In an embodiment, the system furtherincludes a motor/generator drive; wherein the motor/generator drive iscontrolled by the dolly control system to enable torque to be generatedto assist trailer operation. In another aspect, the system furtherincludes a set of sensors in communication with the dolly controlsystem.

In an aspect, the system includes a steering column mountable to theframe portion wherein the active converter dolly is independentlymovable.

In a second aspect of the disclosure, there is provided a method ofcontrolling an active converter dolly including receiving truck andtruck engine information signals from a truck on board diagnostics (OBD)system; processing the truck control signals; and transmittingmotor/generator drive control signals to a motor/generator drive basedon the truck and truck engine information signals.

In another aspect, processing the truck and truck engine informationsignals includes processing the truck and truck engine informationsignals via a power line communicator unit. In a further aspect, thetruck and truck engine information signals includes signals representinga level of braking and the motor/generator drive control signals includesignals to apply a corresponding brake torque. In yet a further aspect,the truck signals includes signals indicating a truck is starting up andthe motor/generator drive control signals include signals to generator atorque to assist start-up of the truck. In another aspect, processingthe truck control signals includes receiving sensor signals; anddetermining motor/generator drive control signals based on the sensorsignals to improve performance and fuel savings for a tractor-trailer.In an embodiment, the sensor signals are global positioning signals(GPS), Inertial Measurement Unit (IMS) sensor signals or real-timetraffic and road information.

In another aspect, processing the truck control signals includesgenerating the motor/generator drive control signals with respect totrailer shunting instructions. In yet another aspect, processing thetruck control signals includes determining motor/generator drive controlsignals to improve tractor-trailer stability and control. In yet afurther aspect, processing the truck control signals includesdetermining motor/generator drive control signals based to assist intractor-trailer back-up operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made, by way of example, to the accompanyingdrawings which show example embodiments of the present application, andin which:

FIG. 1 is a side view of a tractor-trailer including an active converterdolly;

FIG. 2 a is a perspective view of another embodiment of an activeconverter dolly;

FIG. 2 b is a schematic diagram of one embodiment of a charge generatingsystem for an active converter dolly;

FIG. 3 is a perspective view of the active converter dolly;

FIG. 4 is a perspective view of a battery enclosure of the activeconverter dolly;

FIG. 5 a is a schematic view of an active converter dolly controlsystem;

FIG. 5 b is a flowchart outlining one embodiment of controlling anactive converter dolly;

FIG. 5 c is a flowchart outlining one embodiment of transmitting signalsfrom the converter dolly control system;

FIG. 6 is a schematic diagram of another embodiment of an activeconverter dolly for use with a tractor-trailer;

FIG. 7 is a chart outlining motor torque vs. throttle;

FIG. 8 is a chart outlining showing regenerative and friction braketorque blending;

FIG. 9 a is a chart outlining engine torque vs engine speed for oneactive converter dolly operational mode;

FIG. 9 b is a chart outlining engine torque vs engine speed for a secondactive converter dolly operational mode;

FIG. 10 is a schematic diagram of another embodiment of a chargegenerating system;

FIG. 11 is a schematic diagram of a further embodiment of a chargegenerating system;

FIG. 12 is a schematic diagram of a steering mechanism for use with theactive converter dolly; and

FIGS. 13 a and 13 b are charts outlining turning radius with respect todifferent active converter dolly embodiments.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The disclosure is directed at a method and apparatus for an activeconvertor dolly for use in a tractor-trailer configuration. In oneembodiment, the apparatus includes a system to connect a tractor to atrailer. The apparatus further includes a charge generating system fortranslating the mechanical motions or actions of the dolly intoelectricity or electrical energy so that this energy can be used tocharge a battery or to power other functionality for either the dolly orthe tractor-trailer.

Turning to FIG. 1 , a schematic diagram of a tractor-trailerconfiguration is shown. The tractor-trailer 10 includes tractor 13, cabor truck that pulls a pair of trailers 12 (seen as a primary trailer 12a and a secondary trailer 12 b) that are connected to each other via anactive convertor dolly 14. The active convertor dolly 14 connects thetwo trailers 12 a and 12 b together such that they move with respect toeach other when the tractor 13 is in motion.

In the current embodiment, the active convertor dolly 14 includes anapparatus for translating mechanical motion experienced by the dolly 14into an electric charge which allows the dolly 14 to be used for otherapplications. In one embodiment, the electric charge can be used tocharge a battery while in another embodiment, the electric charge may beused to power auxiliary devices like a refrigeration or A/C unit mountedto the tractor-trailer 10. In another embodiment, the charged batterycan be used to jumpstart a dead truck or to supply power to accessorieswhen the engine of the tractor 13 is off. In another embodiment, thecharged battery can be used to assist the tractor by providing torque tothe dolly's wheel through its motor(s)/generator(s). While the activeconvertor dolly 14 may generate charge from other wheels and axleswithin the tractor-trailer 10, such as in a series or parallelimplementation, to charge the battery, in the preferred embodiment, theactive convertor dolly 14 can be seen as a through-the-road (TTR) hybridvehicle as it preferably operates independently from the other axles ofthe trailers 12 of the tractor-trailer 10. This will be described inmore detail below.

Turning to FIG. 2 a , a perspective view of one embodiment of an activeconvertor dolly is shown.

In this embodiment, the active converter dolly 14 includes a frame 24including a wheel supporting portion, or end, 9 along with a tongueportion, or end 8. The frame can be manufactured from differentmaterials such as, but not limited to, high strength steel, carbonfibre, aluminum, or other materials. As will be understood, the dolly 14does not have to be made entirely from one material and may be acombination of at least two different materials. As will be discussed inmore detail below, the lightweight nature of the composite materials mayalso provide a benefit or advantage in terms of fuel savings. In apreferred embodiment, the frame is made from lightweight composites incombination with metal components where required for strength orreinforcement purposes.

A primary trailer connection assembly 7, which in the current embodimentcan be seen as a hitch 26, forms part of the tongue portion 8 and islocated at one end of the frame 24 for connecting the converter dolly 14to the primary trailer 12 a. The connection between the primary trailerand the converter dolly 14 will be well understood by one skilled in theart. Although not shown, the tongue end of the frame 24 may also includesafety chains and at least one wiring harness connection for enabling orsecuring the primary trailer to the dolly 14. Along with the hitchportion, the primary trailer 12 a and the dolly 14 may be connected viaan electric cable which is capable of delivering power from the trailer12 a to the dolly 14. A support leg or apparatus 27 is also attached tothe frame 24 at the tongue end 8.

The dolly 14 has at least one wheel supporting portion 9 or axle. Thewheel supporting portion 9 includes a set of wheels 22 mounted onopposite sides of the frame 24. In the current embodiment, each wheelset includes two wheels to improve the load bearing capacity of theactive converter dolly 14.

According to one embodiment, each wheel set may be separately mounted tothe frame 24. In other words, there is no common axle nor differentialassociated with the opposed wheel sets. Instead each wheel set ismounted to its own electric motor wheel assembly.

In the current embodiment, the secondary trailer mounting assembly 6 canbe seen as a fifth wheel assembly 28 that is mounted to a top of theframe 24. The fifth wheel assembly 28 may include an upwardly facingportion having a slot for receiving a corresponding protrusion from thesecondary trailer for mounting, or attachment, of the secondary trailerto the converter dolly 14. The fifth wheel assembly 28 is preferablysupported by a spring suspension system (not shown).

The active convertor dolly 14 further includes the charge generatingsystem 30 that generates an electric charge during certain mechanicalactions by the dolly 14. The electric charge is preferably used tocharge the battery 32 that is mounted to the frame 24 within anenclosure 34 to protect the battery 32 from any damage. In a preferredembodiment, the enclosure 34 is waterproof and durable. A schematicdiagram of the charge generating system 30 is shown in FIG. 2 b.

As schematically shown in FIG. 2 b , the system 30 includes a set ofelectric motors/generators 36, which in the current embodiment is two,mounted to an electric axle 37 that connects the wheels 22 (as shown inFIG. 2 a ). The motor/generator is used to convert the electric energystored in the battery to mechanical energy by rotating the wheel (motormode) or convert the mechanical energy to electric power (generatormode) through the rotating wheel. In the current embodiment, theelectric motors/generators are preferably located proximate the wheels22 of the dolly 14. Although two motors 36 are shown, it will beunderstood that the system 30 may include only a single motor/generators(such as located along the axle between the two wheels through adifferential) or may include more than two motors/generators. Themotor/generator controls the movement of the tires via the axle 37 basedon signals transmitted from a dolly controller. This will be describedin more detail below. In one embodiment, a motor/generator drive 38receives the electric power generated in the electric motor/generatorthrough regenerative braking for example, of the dolly 14, to charge thebattery 32 and later power the electric motors 36. Regenerative brakingis an energy recovery mechanism which slows a vehicle by converting itskinetic energy into electric form. Another form of energy for recoveryto be generated or translated into electricity may be gravitationalpotential energy due to elevation which can be harvested while thevehicle is driving downhill. Another time of converting kinetic energyinto electric form is when the truck's engine is running at highefficiency and the battery is at low charge.

The convertor dolly 14 may further include a plurality of onboardinstrumentation within the control system or controller that communicatewith equipment, such as sensors 40, that may be used for, among otherapplications, to assist with steering, stability, determining theproximity of the dolly to foreign objects such as barriers andobstacles, or receiving road grade information. In one embodiment, thesensors 40 may be used to assist in aligning the primary and secondarytrailers 12 a and 12 b when the tractor-trailer 10 is moving in reverse.Furthermore, in a preferred embodiment, sensors may be used to helpidentify the relative position of the converter dolly 14 to otherelements or components of the tractor-trailer 10. The output from thesensors can be fed into one or more dolly control systems (preferablylocated within the enclosure 34) where such information can be used tocontrol the dolly 14. A schematic diagram of a dolly control system isshown and described in more detail with respect to FIG. 5 .

FIG. 3 is a schematic rear view of the dolly of FIG. 2 a . Somecomponents of the dolly have been removed for ease of understanding ofthe disclosure. For instance, one wheel set 22 and parts of the framehave been removed.

The charge generation system 30 includes an electric motor/generatorwheel assembly 50 that can be seen as an integrated electric motor wheelassembly. Although not shown, a similar wheel assembly is preferablymounted adjacent the other wheel 22.

In operation, as the tractor-trailer starts to brake, themotor/generator wheel assembly 50 captures the kinetic energy of thedolly whereby this energy may flow via the motor/generator drive 38 tothe battery 32. Typically, the combination of electricmotor(s)/generator(s) 36 and drive 38 converts the kinetic energy intoelectricity before it is transmitted to the battery 32.

The battery and control enclosure 34 is mounted on the dolly frame 24for example but not limited on the sides, or the back as shown in FIG. 2a . As outlined above, the control enclosure 34 is preferably formedfrom a durable waterproof and corrosion resistant material such as acomposite or aluminum, which is also preferably lightweight for fueleconomy reasons. By being both waterproof and corrosion resistant, theenclosure 34 provides a durable compartment for the converter dolly 14.

Turning to FIG. 4 , a perspective view of one embodiment of a batteryenclosure 34 is shown. In the current figure, the walls of the enclosureare shown as being transparent so that the contents of the enclosure canbe seen.

In this embodiment, the enclosure 34 houses a control module 60 whichcan be seen as a battery and control module. The control module 60preferably performs multiple functions for the convertor dolly 14. Inone embodiment, the control module is used to monitor and control thebattery 32. It also be used to control motors/generators through theirdrives for both motoring and generating modes. Furthermore, the controlmodule 60 may monitor and control battery, or batteries charging viaexternal plug-in sources. The control module 60 may also include anintelligent power dispatch system to determine when to power the wheelsvia the motor/generators 36. Furthermore, the control module 60 mayinclude an intelligent steering system to control simultaneousbraking/traction of opposite wheels and/or provide shunting operation ofthe active converter dolly. In another embodiment, the control module 60may be used to set up the charge generating system 30 for regenerativebraking or for auxiliary power depending upon the road circumstances andthe condition of the load on the tractor engine.

The enclosure 34 preferably also houses the battery 32, which in thepreferred embodiment is a modular lithium-ion battery system. Theenclosure 34 may also house a sensor interface 62 which communicateswith the sensors 40 located throughout the dolly. The sensor interface62 may communicate with the sensors 40, to assist, for example, withusing the dolly 10 to direct the steering of the trailer(s) when thetractor trailer is moving in reverse. While shown separately, the sensorinterface 62 can be integrated within the control module 60.

In one embodiment, the enclosure 34 may also house a gyroscopeself-balancing control system 64 and an off-board power interface 66.The gyroscope self-balancing control system 64 may be in communicationwith the dolly control system to transmit signals which can be used forexample, to be part of a self-balancing control system for the converterdolly. In the event that the converter dolly is self-balancing, thepresence of a landing wheel may not be necessary.

The off board power interface 66 may be used to connect the battery 32to off-board charging systems and/or off-board loads. The enclosure 34preferably includes a tractor interface 68 that communicates withtractor engine information system. In a preferred embodiment, thetractor interface 68 is part of the control module 60. The enclosure 34may also house an interface to receive the throttle level (not shown) ofthe main tractor. The tractor and tractor engine information such as butnot limited to throttle level, engine torque, engine speed, etc. areused in the active converter dolly control system via an interface todetermine when to recover and when to expend recovered energy to assistin increasing the fuel economy of the tractor-trailer system.

In one embodiment of the battery enclosure 34, a forward exteriorsurface of the battery enclosure 34 may be configured to reduce drag.Various aerodynamic profiles can be used and the profile shown is notintended to be limiting. In some cases, the low positioning of thebattery enclosure may allow for a ground effect design to be employed,meaning that the shape will take into account both the passage of airfrom in front and past the leading edge, as well as air passing belowthe leading edge between the leading edge and the ground. According to apreferred embodiment of the disclosure, the battery control enclosure islocated at a low level between the wheels such that the weight of thebattery system to be located as low down as is practical to have a lowercentre of gravity to improve road handling and control of the activedolly 14 during transport. In another embodiment, the system may includea lightweight composite chassis (or frame) which is aerodynamic bydesign and includes the enclosures for the batteries and controls.

Turning to FIG. 5 a , a schematic diagram of a dolly control system forthe converter dolly is shown. In the current embodiment, certaincomponents of a trailer which are in communication with the converterdolly control system 500 are also schematically shown.

The converter dolly control system 500 includes an intelligentcontroller 502 which is, in one embodiment, implemented within a centralprocessing unit (CPU). In this embodiment, the intelligent controller502 is in communication with the tractor OBD unit via a power linecommunicator unit 504 to receive the tractor or truck (tractor and truckare used interchangeably here) and tractor engine information. Wirelesscommunication can also be used instead of the power line communicatorunit 504 to connect the tractor OBD to the dolly control system 502. Thedolly control system 502 also communicates with the set of sensors 40,such as but not limited to, a Global Positioning Sensor (GPS) or anInertial Measurement Unit (IMU) sensor. The intelligent controller 502is also in two-way communication with a battery and battery managementsystem (BMS) unit 506 and a motor/generator drive 508. The battery andBMS unit 506 is also connected to the drive 508. The motor/generatordrive 508 is further connected to, or in communication with, the set ofmotors/generators 36 (see FIG. 2 b ) that are associated with anindividual wheel 22. As schematically shown in FIG. 2 b , the number ofmotor/generators in the current set is two.

The intelligent controller 502 is also connected to a database 510including road grade information 512 which can be stored within adatabase or based on sensor information, or real time road informationby connecting the dolly intelligent controller 502 to wireless network.Separate connectors, seen as an electric connector from the trailer 518and an electric connector to the trailer 520 are also connected to theelectric line 516. As will be understood, one of the connectors 518 or520 is connected to the primary trailer and the other connector isconnected to the secondary trailer.

The intelligent controller 502 may further include an interface of amodule allowing the controller to be monitored by a user over theInternet.

The truck or tractor includes a power line communication unit 522 thatconverts information from a vehicle on-board diagnostics (OBD) system524 to be sent via the truck electric lines. In another embodiment, theOBD information can be converted and transmitted wirelessly. The truckor tractor power line communication unit 522 is connected to theelectric line 526 which, in turn, is connected to an electric connectorto a trailer 528. In use, the electric connector to trailer 528 and theelectric connector from trailer 518 are connected via a cable to eachother to deliver power and OBD information from the truck to all theconnected trailers and dollies to the tractor.

In the current embodiment, the transmission of signals between thevehicle OBD 524 and the intelligent controller 502 is via the electricline where the signals from the vehicle OBD are converted by the powerline communicator unit 522 which then uploads the converted signal tothe truck electric line. At the dolly end, the signals are received bythe power line communication unit 504 which then extracts the convertedOBD signals and then decrypts or converts these signals into a formatunderstood by the controller 502. In another embodiment, the signals maybe communicated or transmitted wirelessly between the vehicle OBD andthe intelligent controller.

In operation, as the tractor-trailer is in motion, the intelligentcontroller 502 receives and transmits signals to the other components ofthe controller system. For instance, the intelligent controller 502 cancommunicate with the sensors 40 to receive signals representing variousdata that the controller 502 can use to assist in improving operation ofthe tractor-trailer and the dolly.

A method of convertor dolly control is shown with respect to FIG. 5 b .As the truck is driving, the vehicle OBD 524 collects various truckinformation with respect to characteristics of the truck. For instance,this information may include, but is not limited to, a position of thebrake pedal or braking torque, amount of torque being generated by theengine, the speed of the engine, etc. The sensors may also collectsensor information associated with various dolly characteristics such aslisted above. Other information may include road grade information, mapinformation or any real-time information and the like.

All, or parts of this, information is then transmitted to, and receivedby, the intelligent controller 502 within the dolly (1000). In terms ofthe signals received from the vehicle OBD, in one embodiment, thedigital signals from the vehicle OBD 524 are converted by the power linecommunication unit 522 and then transmitted over the truck electric line526. These signals are then retrieved, or received, by the power linecommunicator unit 504 within the dolly and then extracted, and, ifnecessary, re-converted before being received by the controller 502. Aswill be understood, the power line communicator unit 504 converts theextracted signals into a format understandable by the controller 504. Aswill be understood, due to the connection between the dolly and thetrailers (via the connectors 518 and 520), the dolly control system 502has access to any signals and electricity that is transmitted over theelectric line.

In another embodiment of digital signal transmission, the digitalsignals may be transmitted wirelessly from the vehicle OBD 524 to thecontroller 502.

After the controller 502 receives the digital signals, the controllerprocesses the signals (1002) and then generates dolly control signals tocontrol the dolly (1004) based on the digital signals. The dolly controlsignals may also be seen as motor-generator drive control signals.

For instance, if the truck is braking, the controller 501 may receivedigital signals representing the level of braking being applied to thetruck. In one embodiment this is determined by the vehicle OBD bymonitoring the position of the brake pedal within the truck. Afterreceiving the digital signals, either directly from the vehicle OBD orconverted by the power line communicator unit, the controller cangenerate and send a signal to the motor/generators 36 (via themotor/generator drive 508) to apply a corresponding regenerative braketorque. In this manner, during this regenerative braking, the batterycan be charged based on the braking torque value calculated by thecontroller.

In another embodiment, the controller 502 may receive a digital signalindicating that the truck is being started. If the battery is charged orhas some charge, the controller may generate and transmit a signal tothe motor/generator to apply or generate a torque to assist start-up ofthe truck to improve the efficiency of the truck motor.

In another embodiment, if the SOC within the dolly's battery is low,signals relating to the truck engine's maximum efficiency may bereceived by the controller whereby the controller may then generate andtransmit a signal to the charge generating system to charge the batterywhere possible.

Turning to FIG. 5 c , a flowchart outlining a method of communicationfrom the dolly control system is shown. Initially, dolly informationsignals, which are typically digital, may be converted (1010) if theyare being transmitted to a truck driver over the electric line asdiscussed above. The dolly information may include information relatingto the dolly's position, the battery charge, or the like.

The dolly information signals are then transmitted (1012) to specifieddestinations or individuals, such as, but not limited to, the truckdriver or a fleet manager. As will be understood, the signals may betransmitted wireless or via the electric line to the truck driver. Thesignals being transmitted to the fleet manager is preferably performedwirelessly.

The active converter dolly 14, as outlined above, is a TTR hybridsystem. As such, the dolly of the disclosure operates in differentoperational modes.

In one mode, the active dolly does not participate in extracting orproviding power to the tractor-trailer system. In this mode theconverter dolly will be passive. In another mode, whereby auxiliaryloads (for example cabin's or trailer's A/C system), is driven by thecharge generating system of the dolly or the stored energy in itsbattery. In yet another mode, the energy in the dolly's battery is usedto provide traction torque in the dolly's tires to assist the motion ofthe tractor-trailer system. In another mode, the dolly is used toextract and convert the mechanical power in the rotation of its wheelsinto electric power via its motor/generators. The electric power thencan be used to be stored in the battery and/or run auxiliary devices ofthe truck-tractors. This mode is activated during regenerative brakingor when the truck-trailer drives downhill, or when battery needs to becharged in which it is activated when the engine is operating at highefficiency.

In further designing one embodiment of the dolly, certain drivingconditions are considered. These conditions may include, but are notlimited to, acceleration—when the vehicle's velocity is increasing;deceleration—when the driver releases the accelerator pedal and maypress the brake pedal; and cruising—when the road load and the vehicle'svelocity are constant.

During acceleration, if there is enough charge in batteries, where thestate of charge (SOC) of the battery is greater than the SOC thresholdacceleration, the dolly assists the truck's powertrain via the electricmotor associated with the dolly wheels, provides an additional boosttorque in addition to the torque generated by the tractor. In oneembodiment, the SOC threshold acceleration can be a predeterminedthreshold calculated via experiments or system optimizationcalculations. This boost torque depends on vehicle speed, the battery'sSOC, and accelerator pedal position. A sample map for electric motoroutput during acceleration at a sample vehicle speed equal to 50 km/hfor various battery SOCs is shown in FIG. 7 .

During deceleration, if the battery is or batteries are not fullycharged, dolly typically does not assist the truck nor add any load tothe truck to extract any energy. During coasting and based on thebattery's SOC, the dolly could extract power via the generator forcharging the batteries. However, when the brake pedal is depressed,parallel regenerative braking is actuated. Depending on vehicle speedand consequently, the generator's rotational speed, for approximately10-20% of initial brake pedal travel, the friction brakes are notengaged and only regenerative braking is applied. During harder brakingconditions, depending on the value of generator speed and max torque,the braking energy may not completely regenerated. In these situations,the excessive amount of braking torque is applied by friction braking,as shown in FIG. 8 . This process is called brake torque blending.

During cruising, depending on the status of load, or drive torque,relative to optimum load, or drive torque, the dolly can be seen asassisting the truck powertrain, being in active, or extracting power viathe generator. In this situation, if the truck powertrain torque, isgreater than the optimum torque of the engine at that speed, the dollywill be in assist mode, in which electric motor provides a boost torquein addition to the truck torque output, as shown in FIG. 9 a .Consequently, there is a lower torque request from the engine due to theavailable motor torque, which results in a more-efficient tractoroperating point. Finally, if the engine toque is less than the optimumload, or drive torque, the dolly, depends on the SOC of it battery, willbe in charging mode and the truck powertrain delivers its power to theload and the load delivers power to electric powertrain, as shown inFIG. 9 b . In this situation, some portion of engine power is stored inthe batteries by the generator, and the extra requested torque from theICE moves the current ICE operating point to a more efficient one.

With respect to a specific embodiment of the active converter dolly,certain characteristics of the dolly are required. More specifically,power and performance; powertrain configuration and steerability arepreferably taken into account in the design of this embodiment of anactive converter dolly.

With respect to the powertrain configuration, two scenarios, seen as anin-wheel motor embodiment and a drive axle embodiment can be considered.

For the in-wheel motors embodiment, in this configuration, the chargegenerating system 30 includes an axle with two in-wheel motors, such asschematically shown in FIG. 10 . As shown in FIG. 10 , the dolly 14 isconnected to the secondary trailer 12 b. The motors 36 can provide therequired power for driving, and by applying different traction forces,it can play the role of steering system. While this configuration mayrequire a higher level of modification to be retro-fitted into existingconverter dollies, it is more suitable for Vehicle Dynamic Control (VDC)applications because the left and right motors can provide differenttraction/braking torque. By controlling this properly, a corrective yawmoment is formed, which can be used to improve dynamical behaviour ofthe combination of the tractor, trailers, and the convertor dolly.

For the drive-axle embodiment, in this configuration, the axle 37 is adrive axle such as schematically shown in FIG. 11 . Unlike the system ofFIG. 10 , the level of modification for this configuration is lower.Furthermore, the motor/generator reduction gear can also be embeddedinto the axle (double reduction axle).

When the active dolly is disconnected from a primary trailer but stillconnected to a secondary trailer, the active dolly can be used to movethe secondary trailer without having to go through the hassle ofre-mounting the primary trailer. With respect to steerability, in thein-wheel motor embodiment, the steering could be altered by differentialtorque applied by each motor. In the drive-axle embodiment, a steeringmechanism may be integrated with the converter dolly. A schematic of thesteering mechanism that can be used for an active convertor dolly isshown in FIG. 12 . The steering can be achieved by using a motor. Eitheran electric or a hydraulic linear actuator can also provide theretractability of steering mechanism, which can also be seen as a thirdwheel assembly. However, since using the hydraulic actuator requiresadditional power sources and accessories (hydraulic power andconnections), it is preferable to use an electric linear actuator.

Using the related equation of motion for the articulated vehicles, thesteerability of both configurations were investigated. FIGS. 13 a and 13b illustrate the turning radius of the trailer equipped with an activeconvertor dolly with differential torque steering (FIG. 13 a ) andsteering mechanism (FIG. 13 b ) configurations.

It can now be appreciated that the active dolly does not only improvefuel economy when it is attached to the tractor-trailer but can also beused to shunt a trailer when it is not attached to a trailer with addinga steering mechanism. Although not shown, a steering wheel, joystick, orother interfaces can also be included to communicate with the dollycontroller to enable a driver locally or remotely to steer the dolly. Assuch, the dolly can be used to shunt the secondary trailer around astaging area even when the secondary trailer is disconnected from thetractor. This may be to place the secondary trailer in position forloading or unloading, or to place it in position for being attached to atrailer. Because the dolly is equipped with a steering system and by thedolly control system, the active dolly can be directed or steered intoposition. In a preferred embodiment, the steering can be manuallyapplied, such as by way of a remote control device. Such a device couldbe a joystick, smart phone or tablet device which includes a softwareaccess to the steering control or mechanism. In this way the activedolly can be controlled remotely while it is being maneuvered intoposition. Collision avoidance sensors may also be used to help avoidaccidents. These may be mounted on the secondary trailer or may bemounted on the active dolly in a way that permits the dolly sensors tosee past the edges of the secondary trailer for collision avoidance.

Turning to FIG. 6 , another schematic embodiment of an active converterdolly in a B train, in which the active converter is part of the leadtrailer. The fifth wheel assembly sits on the rear axle of the leadtrailer. Similar to the embodiment discussed previously, A train, theactive dolly in B train configuration is capable of adding power todrive the trailer and to being able to capture energy from regenerativebraking. In B train active dollies, at least one of the axels iselectrified as discussed above for adding power to drive the trailer andto being able to capture energy from regenerative braking. Similarly, inA train active dollies with multiple axles, at least one of the axels iselectrified. Electrifying more axels will improve the fuel efficiencyand performance of the active dolly.

According to another aspect of the disclosure, the converter dolly mayinclude a central axle, one electric motor and a differential. In thiscase there is less space to house the enclosure between the wheel sets,however, the other aspects remain the same. The battery enclosurerequires an adaptation to permit the axle to traverse the compartmentand the motor also needs to be connected through the differential.However, even with a central transverse axle, this second embodimentpreferably includes the aerodynamically efficient, lightweight,waterproof and corrosion resistant battery enclosure and aninstrumentation package of appropriate modules to allow for interfacingwith the main tractor motor control system, to interface with theproximity sensors to provide a back-up steering system, to interfacewith a remote controller to permit the dolly to be remotely steeredaround even when disconnected for the tractor trailer train and willallow the dolly to operate equally well in forward or reverse.

In one aspect, the apparatus of the disclosure provides advantages overcurrent converter dollies. For instance, in a preferred embodiment, theactive converter dolly of the disclosure reduces fuel consumptionemission levels. In another embodiment, the active dolly may operate toassist in fulfilling a power demand (acceleration, grade ability andmaximum, or highest, cruising speed) of the tractor-trailer. In anotherembodiment, the disclosure is directed at maintaining a battery's stateof charge (SOC) within a reasonable level, for self-sustaining operationwhereby no external charging is required. Also, the disclosure isdirected at an active converter dolly that may be able to harvestbraking energy to generate electricity.

It will be appreciated by those skilled in the art that variousmodifications and alterations can be made to the present inventionwithout departing from the scope of the invention as defined by theappended claims. Some of these have been suggested above and others willbe apparent to those skilled in the art. For example, although apreferred form of the present disclosure includes separate motors foreach wheel set, the present invention can also be used with a cross axleand differential in and single electrical power source, provided thesame provides enough total energy to hybridize the truck travel.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments; however the specific details are not necessarilyrequired. In other instances, well-known electrical structures andcircuits are shown in block diagram form in order not to obscure theunderstanding. For example, specific details are not provided as towhether the embodiments described herein are implemented as a softwareroutine, hardware circuit, firmware, or a combination thereof.

The above-described embodiments are intended to be examples only.Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art without departingfrom the scope, which is defined solely by the claims appended hereto.

Certain adaptations and modifications of the described embodiments canbe made. Therefore, the above discussed embodiments are considered to beillustrative and not restrictive.

What is claimed is:
 1. An active converter dolly comprising: a frameportion including a trailer/truck connecting portion and a trailerconnecting portion, the trailer connecting portion comprising a fifthwheel configured to receive a fifth wheel connector of a semi-trailer; afirst wheel rotatably coupled to the frame portion and disposed on afirst side of the frame portion; a second wheel rotatably coupled to theframe portion and disposed on a second side of the frame portionopposite to the first wheel; a first motor operably coupling the firstwheel to the frame portion; a second motor operably coupling the secondwheel to the frame portion; and a controller operably coupled,independently, to the first motor and to the second motor; wherein: thefirst motor is operable, via the controller, in at least a drive modefor providing torque to the first wheel; and the second motor isoperable, via the controller, in at least a drive mode for providingtorque to the second wheel.
 2. The active converter dolly as claimed inclaim 1; wherein: the first motor is an in-wheel motor disposed withinthe first wheel; and the second motor is an in-wheel motor disposedwithin the second wheel.
 3. The active converter dolly as claimed inclaim 1; wherein: the controller is operable such that the torqueprovided by the first motor to the first wheel, and the torque providedby the second motor to the second wheel, are the same.
 4. The activeconverter dolly as claimed in claim 1; wherein: the controller isoperable such that the torque applied by the first motor to the firstwheel, and the torque applied by the second motor to the second wheel,are different.
 5. The active converter dolly as claimed in claim 1;further comprising: a steering control system operably coupled,independently, to the first wheel, via the first motor, and to thesecond wheel, via the second motor, for applying different tractionforces to said first wheel and to said second wheel, for providingsteering control of the active converter dolly.
 6. The active converterdolly as claimed in claim 1; further comprising: a yaw control systemoperably coupled, independently, to the first wheel via the first motorand to the second wheel via the second motor, such that the first motorapplies a first traction or braking torque to the first wheel, and thesecond motor applies a second traction or braking torque to the secondwheel; wherein: the first traction or braking torque and the secondtraction or braking torque are different.
 7. The active converter dollyas claimed in claim 1; further comprising: at least one batteryelectrically coupled, independently, to the first motor and to thesecond motor for providing electrical power to the first motor and tothe second motor, respectively.
 8. The active converter dolly as claimedin claim 7; wherein: at least one of the first motor and the secondmotor is a motor/generator; and the motor/generator is further operablein a generator mode for converting kinetic energy generated by rotationof the first wheel or the second wheel, that is operably coupled to themotor/generator, into electrical energy, and storing the electricalenergy on the battery.
 9. The active converter dolly as claimed in claim8; wherein: the controller is operably coupled to the motor/generatorfor selectively activating the motor/generator in either the drive modeor the generator mode.
 10. The active converter dolly as claimed inclaim 9; wherein: the controller is configured for: (i) receiving truckand truck engine information from a truck on-board-diagnostics (OBD)system; and (ii) transmitting a signal to the motor/generator forselectively activating the drive mode or the generator mode based on thereceived truck and truck engine information.
 11. The active converterdolly as claimed in claim 8; wherein: while the motor/generator isoperating in the generator mode, a regenerative braking force is appliedto the first wheel or to the second wheel, that is operably coupled tothe motor/generator, such that the kinetic energy is converted intoelectrical energy via regenerative braking, the electrical energy beingstored on the battery.
 12. The active converter dolly as claimed inclaim 8; wherein: while the motor/generator is operating in thegenerator mode, a regenerative braking force is applied to the firstwheel or to the second wheel, that is operably coupled to themotor/generator, via the motor/generator, such that the kinetic energyis converted into electrical energy via regenerative braking, theelectrical energy being used to power auxiliary devices.
 13. The activeconverter dolly as claimed in claim 12; wherein: the auxiliary devicesinclude a refrigeration unit or an A/C unit for a tractor/trailer. 14.The active converter dolly as claimed in claim 1; wherein: the firstwheel is mounted on a first drive shaft, the first motor being operablycoupled to the first wheel via the first drive shaft; and the secondwheel is mounted on a second drive shaft, the second motor beingoperably coupled to the second wheel via the second drive shaft.
 15. Theactive converter dolly as claimed in claim 7; wherein: the first motoris a first motor/generator; and the second motor is a secondmotor/generator; and the first motor/generator is further operable in agenerator mode, for converting kinetic energy generated by rotation ofthe first wheel into electrical energy, and storing the electricalenergy on the battery; and the second motor/generator is furtheroperable in a generator mode, for converting kinetic energy generated byrotation of the second wheel into electrical energy, and storing theelectrical energy on the battery.
 16. The active converter dolly asclaimed in claim 15; wherein: the controller is operably coupled,independently, to the first motor/generator and to the secondmotor/generator for selectively activating the first motor/generator andthe second motor/generator, independently, in either the drive mode orthe generator mode.
 17. The active converter dolly as claimed in claim16; wherein: the controller is operable such that: while the firstmotor/generator and the second motor/generator are operating in thedrive mode, the first motor/generator provides a first torque to thefirst wheel and the second motor generator provides a second torque tothe second wheel, the first torque and the second torque being the same.18. The active converter dolly as claimed in claim 16; wherein: thecontroller is operable such that: while the first motor/generator andthe second motor/generator are operating in the drive mode, the firstmotor/generator provides a first torque to the first wheel and thesecond motor generator provides a second torque to the second wheel, thefirst torque and the second torque being different.
 19. The activeconverter dolly as claimed in claim 16; wherein: the controller isoperable such that: while the first motor/generator and the secondmotor/generator are operating in the generator mode, a regenerativebraking force is applied, independently, to the first wheel and to thesecond wheel, such that the kinetic energy of each of the first wheeland the second wheel is converted into electrical energy viaregenerative braking, the electrical energy being stored on the battery.20. The active converter dolly as claimed in claim 1; furthercomprising: a self-balancing control system operably coupled to thefirst motor and to the second motor, the self-balancing control systembeing operable such that a different torque is applied to the firstwheel, via the first motor, than is applied to the second wheel, via thesecond motor.
 21. The active converter dolly as claimed in claim 20;wherein: the self-balancing control system includes a gyroscope.
 22. Theactive converter dolly as claimed in claim 1; wherein: the fifth wheelconnector is a kingpin.
 23. The active converter dolly as claimed inclaim 1; wherein: the semi-trailer is a first semi-trailer; and thetrailer/truck connecting portion includes a trailer connection systemfor connecting the frame portion to a second semi-trailer.
 24. Theactive converter dolly as claimed in claim 23; wherein: the trailerconnection system includes a pintle hook system for connecting thetrailer/truck connecting portion to the second semi-trailer.
 25. Anactive converter dolly comprising: a frame portion including atrailer/truck connecting portion and a trailer connecting portion, thetrailer connecting portion comprising a fifth wheel configured toreceive a fifth wheel connector of a semi-trailer; at least one wheelrotatably coupled to the frame portion; a motor/generator operablycoupling the at least one wheel to the frame portion; a batteryelectrically coupled to the motor/generator; wherein: themotor/generator is operable in: a drive mode for applying torque to theat least one wheel; and a generator mode for converting kinetic energygenerated by rotation of the at least one wheel into electrical energyand storing the electrical energy on the battery.
 26. The activeconverter dolly as claimed in claim 25; further comprising: a controlleroperably coupled to the motor/generator; wherein: the controller isconfigured for selectively activating the motor/generator in either thedrive mode or the generator mode.
 27. The active converter dolly asclaimed in claim 26; wherein: while the motor/generator is operating inthe generator mode, a regenerative braking force is applied to the atleast one wheel, via the motor/generator, such that the kinetic energyof the at least one wheel is converted into electrical energy viaregenerative braking, the electrical energy being stored on the battery.28. The active converter dolly as claimed in claim 26; wherein: whilethe motor/generator is operating in the generator mode, a regenerativebraking force is applied to the at least one wheel, via themotor/generator, such that the kinetic energy of the at least one wheelis converted into electrical energy via regenerative braking, theelectrical energy being used to power auxiliary devices.
 29. The activeconverter dolly as claimed in claim 26; wherein: the controller isconfigured for receiving trailer/truck engine information from anon-board-diagnostics (OBD) system and selectively activating the drivemode or the generator mode based on the received trailer/truck engineinformation.
 30. The active converter dolly as claimed in claim 27;wherein: the at least one wheel includes a first wheel rotatably mountedto a first side of the frame portion, and a second wheel rotatablymounted to a second side of the frame portion such that the first wheeland the second wheel are disposed opposite, or substantially opposite,to one another; and the motor/generator includes a first motor/generatoroperably coupled to the first wheel and a second motor/generatoroperably coupled to the second wheel.
 31. The active converter dolly asclaimed in claim 30; wherein: the first wheel is mounted on a firstdrive shaft, the first motor/generator being operably coupled to thefirst wheel via the first drive shaft; and the second wheel is mountedon a second drive shaft, the second motor/generator being operablycoupled to the second wheel via the second drive shaft.
 32. The activeconverter dolly as claimed in claim 27; wherein: the at least one wheelincludes: a first wheel rotatably mounted to a first side of the frameportion; and a second wheel rotatably mounted to a second side of theframe portion such that the first wheel and the second wheel aredisposed opposite, or substantially opposite, to one another; wherein:the first wheel is mounted on a first drive shaft; the second wheel ismounted on a second drive shaft; and the motor/generator is operablycoupled to the first wheel and to the second wheel via a differentialinterconnecting the first drive shaft and the second drive shaft. 33.The active converter dolly as claimed in claim 27; further comprising:an axle coupled to the frame; wherein: the at least one wheel includes:a first wheel mounted to the axle such that the first wheel is disposedon a first side of the frame portion; a second wheel mounted to the axlesuch that the second wheel is disposed on a second side of the frameportion opposite to the first wheel; and the motor/generator is operablycoupled to the axle such that torque is transmitted to both the firstwheel and the second wheel, via the axle, while the motor/generatoroperates in the drive mode, and a regenerative braking force istransmitted to both the first wheel and the second wheel, via the axle,while the motor/generator operates in the generator mode.
 34. The activeconverter dolly as claimed in claim 25; wherein: the fifth wheelconnector is a kingpin.
 35. The active converter dolly as claimed inclaim 25; wherein: the semi-trailer is a first semi-trailer; and thetrailer/truck connecting portion includes a trailer connection systemfor connecting the frame portion to a second semi-trailer.
 36. Theactive converter dolly as claimed in claim 35; wherein: the trailerconnection system includes a pintle hook system for connecting thetrailer/truck connecting portion to the second semi-trailer.
 37. Anactive converter comprising: a frame portion including a trailer/truckconnecting portion and a trailer connecting portion; a kingpin couplerdisposed at the trailer/truck connecting portion of the frame forcoupling the frame to a fifth wheel of a truck; a fifth wheel disposedat the trailer connecting portion of the frame for coupling the frame toa kingpin coupler of a semi-trailer; a pair of wheels rotatably coupledto the frame; at least one motor operably coupled to at least one wheelof the pair of wheels; an energy storing device for storing electricalenergy and supplying electrical energy to the at least one motor; and acontroller operably coupled to the at least one motor; wherein: the atleast one motor is operable, via the controller, in at least a drivemode for providing torque to the at least one wheel of the pair ofwheels.
 38. The active converter dolly as claimed in claim 37, wherein:the at least one motor comprises: a first in-wheel motor disposed withina first wheel of the pair of wheels; and a second in-wheel motordisposed within a second wheel of the pair of wheels.
 39. The activeconverter dolly as claimed in claim 38, wherein: the first in-wheelmotor comprises a first motor/generator; the second in-wheel motorcomprises a second motor/generator; the first motor/generator is furtheroperable in a generator mode, for converting kinetic energy generated byrotation of the first wheel into electrical energy, and storing theelectrical energy on the energy storing device; and the secondmotor/generator is further operable in a generator mode, for convertingkinetic energy generated by rotation of the second wheel into electricalenergy, and storing the electrical energy on the energy storing device.